Kelly Ziemba, left, of Cheshire, Mass., and Bethaney Hagmaier of Dalton, Mass. have their picture taken in an American Gothic cut out in Homegrown Village at Farm Aid 2013 at SPAC Saturday Sept. 21, 2013, in Saratoga Springs, NY. (John Carl D'Annibale / Times Union)

"This concert is about you and me. It's about us. It's about the food we eat, and the people who grow it," Neil Young declared at the Saratoga Performing Arts Center on Saturday night. "Bring good sense and sustainability back. Support your family farms, and eat good food."

Yes, Farm Aid had come to Saratoga Springs, and so too did the crowd, seemingly packed into every square inch of space at SPAC from fence to shining fence. And they came for the music as much as the message.

It was a nearly 12-hour marathon festival with 20 acts, including a surprise special guest. It was an eclectic and at times electrifying array of performers and musical styles, kicking off at noon with the lone Capital Region representatives, the Parlor, and closing with the 80-year-old grand old man of country music (and the Farm Aid instigator), Willie Nelson.

Nelson whipped through a nice mix of his hits ("Good-Hearted Woman," "Mamas, Don't Let Your Babies Grow Up to Be Cowboys," his traditional opener "Whiskey River") with the zen of "Still Is Still Moving to Me," a duet with up-and-coming Texas singer Lily Meola on "Will You Remember Mine" and best of all, a duet with his son Lukas on Pearl Jam's "Just Breathe." However, Nelson was only one of the Big Four headliners, which also included Neil Young, John Mellencamp and Dave Matthews, all members of Farm Aid's Board of Directors.

Young – who also played with his wife, Pegi Young, and her band, the Survivors, earlier in the day – offered an intriguing set. Introduced by Mellencamp as "one of the best songwriters of our generation, if not the best," Young offered only two of his own songs – "Old Man" and "Heart of Gold," both from 1972's "Harvest" – during his solo set. He spent the rest of his set honoring other songwriters, including Bob Dylan, Gordon Lighfoot (a lovely rendition of "Early Morning Rain"), Tim Hardin and more.

The rain came in during Mellencamp's set, but it didn't dampen his fire, especially when he and his band ramped up his back-to-back set-closers, "Crumblin' Down" and "Pink Houses." Crowd favorite Matthews was seated center stage with right-hand man Tim Reynolds doing the heavy guitar work as they nailed the opening "Save Me" and a tasty, slide guitar-fueled rendition of "Cornbread" with a just a pair of acoustic guitars.

But the emotional highpoint of the day came when Mellencamp introduced a previously unannounced special guest, and 94-year-old Pete Seeger walked onstage with his banjo to lead the crowd in a sing-along of "If I Had a Hammer." And if that wasn't enough, Seeger brought the Big Four out with him to sing Woody Guthrie's classic "This Land Is Your Land," adding a new and timely verse that ended with the lyric, "New York was meant to be frack-free."

Upcoming: That wraps up the 2103 season at SPAC, but you can catch several Farm Aid performers in upcoming shows around town, including the Parlor at Valentine's Music Hall on Saturday, October 26 and Toad the Wet Sprocket at the College of St. Rose's Massry Center on Sunday, Nov. 3.